Viral Coefficient Calculator (K-Factor)
Free CalculatorTurn your users, invites sent and invite conversion rate into your viral coefficient (K) β instantly and privately.
100% private
Runs in your browser β no numbers leave your device.
Your numbers
Current users who can invite others.
Average invites each user sends.
Share of invites that become new users.
Viral coefficient (K)
1
New users each user generates. K β₯ 1 means self-sustaining viral growth; below 1 growth decays.
New users from this cycle
1,000
Existing users Γ K.
How it works
Enter your users
Start with the number of active users who can invite.
Add invites per user
Enter the average invites each user sends.
Add conversion rate
Enter the share of invites that become new users.
Read your K-factor
Your viral coefficient and new users update live.
Turn installs into invites
Reverze rebuilds your App Store screenshots into higher-converting creative β so more of your traffic becomes users who invite.
What is a viral coefficient calculator?
A viral coefficient calculator works out your K-factor: the number of new users each existing user generates through invites. The formula is simple β multiply the average invites each user sends by the share of those invites that convert into new users. If every user sends 5 invites and 20% convert, your viral coefficient is 1.0, meaning each user brings in exactly one more. This tool splits that into your K-factor and the new users a single cycle produces.
The magic number is K β₯ 1. When your viral coefficient is 1 or higher, every cohort more than replaces itself and growth becomes self-sustaining and exponential β you get compounding installs without spending more on acquisition. Below 1, each viral cycle is smaller than the last and growth decays, so invites amplify paid and organic channels rather than carrying growth alone. Raising either lever β more invites sent, or a higher invite conversion rate β pushes K up.